The village in Ottoman Turkish was called Aşağı Kotor.[3] In statistics gathered by Vasil Kanchov in 1900, Kato Kottori was populated by 174 Christian Albanians and 600 Bulgarians.[4] Kanchov wrote that Christian Albanians of the late Ottoman period in Kato Kottori were increasingly being assimilated by its Bulgarian population.[5]
In the early twentieth century, Kato Kotori was involved with the Bulgarian national movement.[5][6]
During the 1940s, kin relations began to be formed between the Slavophone (Dopioi) and Arvanite populations of the village.[7] Villagers from both groups together attended school, partook in social events and looked after each other during the Second World War and Greek Civil War.[7]
Ydroussa had 456 inhabitants in 1981.[8] In fieldwork done by anthropologist Riki Van Boeschoten in late 1993, (Kato) Ydroussa was populated by Slavophones and Arvanites.[8] The Macedonian language was spoken in the village by people over 30 in public and private settings.[8] Children understood the language, but mostly did not use it.[8]
In the late 1990s, in fieldwork done by Ioannis Manos, much of the Ydroussa village population self identified as Dopioi, a designation used by Slavophones of the Florina region and the remainder as Arvanites.[9] There were seldom elderly individuals with knowledge of Arvanitika.[7]
